ISGS study – (39MB PDF)
Human Health Issues
Iowa Concentrated Animal Feeding Operations (CAFO) Air Quality Study
Final Report
Iowa State University and The University of Iowa Study Group
February 2002
Water-soluble, ammonia is rapidly absorbed in the upper airways, with the result of damaging upper airway epithelia. Moderate concentrations (50-150 ppm) can lead to severe cough and mucous production; higher concentrations (>150 ppm) may cause scarring of the upper and lower airways In addition to pulmonary disease, exposure to ammonia also leads to irritation of the eyes, sinuses, and skin.
Hydrogen sulfide is one of the most important of the gases arising from the storage, handling, and decomposition of animal wastes. Smelling like rotten eggs, this gas that is recognized as both an irritant and an asphyxiant, is a prominent component of odorants released from CAFOs. For community exposures, EPA has recommended a reference concentration for long-term exposure of 7 ppb (See Chapter 8.0 for full discussion). Levels as high as 1,000 ppm have been reported (Donham and Gustafson, 1982) following the perturbation of manure lagoons, and levels greater than 100 ppm are considered immediately hazardous to life and health.
The air in CAFOs is contaminated with high concentrations of particulates, approximately one quarter of which is protein; about one third of suspended dust is considered respirable ( 10 microns in diameter, PM10). Particles which settle in the upper airways are associated with asthma and bronchitis; smaller particles may be absorbed and have systemic effects including, in studies of urban air pollution, increased rates of cardiac death. In addition to direct inflammatory response to inhaled allergens, dust can also convey inflammatory and/or irritating gases or chemicals (such as ammonia, hydrogen sulfide, or endotoxin) deeper into the lung, thereby enhancing their toxic effects.
An important component of the environment released from CAFOs is microbiologic in origin. Some of the microorganisms that are present in the CAFO environment are human pathogens, creating a potential risk of infection for those exposed to these agents. Exposure to protein antigens derived from plants, animals, and microbes are known to cause a variety of medical problems. Asthma may also be caused or exacerbated by exposure to conditions common in CAFOs.
CAFOs contain, among other compounds, high concentrations of grain dust, dust mites, animal dander, pollen grains, molds and fungal spores, and dried fecal particles, each of which may induce or exacerbate asthma. Proximity to CAFOs, and periodic/seasonal agricultural activities (e.g., agriculture chemical and manure applications), are frequently cited by rural asthma patients as exposures resulting in asthma exacerbation making asthma control more difficult.
While CAFO odors have long been recognized as a neighborhood nuisance, recent studies have suggested that odiferous exposures emitted from CAFOs may well have adverse health effects They observed that health symptoms have been reported with increasing frequency from low level exposures from manures and biosolids; “the most frequently reported health complaints include eye, nose, and throat irritation, headache, nausea, diarrhea, hoarseness, sore throat, cough, chest tightness, nasal congestion, palpitations, shortness of breath, stress, drowsiness, and alteration in mood”.
Numerous occupational studies have documented significant increases in respiratory disease and other respiratory adverse health effects, including CAFO-related deaths, acute and chronic respiratory diseases and associated symptoms and acute losses in exposure-related lung function and progressive respiratory impairment, among those who work in CAFOs. However, it is recognized that the CAFO workforce is generally healthy, while those in the general community, including children, the elderly, those with chronic impairments such as pre-existing asthma or chronic obstructive pulmonary disease, are expected to be much more susceptible to CAFO exposures.
There is experimental and epidemiological evidence that very low levels of exposures to ammonia, hydrogen sulfide, known to be ambient air toxic gases arising from CAFOs, may result in adverse health effects among healthy volunteers and community residents. These findings support a conclusion that CAFO air emissions constitute a public health hazard.
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Air Pollution
September 2007 Senate Testimony by the National Association of Clean Air Agencies (NACAA)… on the human health impacts of CAFOs. Threemile Canyon Farms in Oregon, in which A.J. Bos (the California investor behind this project) was a partner, is mentioned on page 3.
Air emissions from CAFOs can harm human health and the environment. These harmful emissions include ammonia, hydrogen sulfide and particulate matter, including fine particulate matter (PM2.5).
Human exposure to ammonia triggers respiratory problems, causes nasal and eye irritation and in large enough amounts can be fatal. Ammonia also contributes directly to the formation of PM2.5, which causes severe health effects in humans, including death, heart attacks and increased severity of asthma attacks, as well as visibility impairment.
Hydrogen sulfide is a toxic air pollutant that can cause severe health effects, even death, at high concentrations of exposure. Air emissions from CAFOs are, by no means, trivial. In fact, CAFO ammonia emissions represent half the U.S. ammonia emissions inventory.
Emissions of ammonia from the largest CAFOs approach and even dwarf those of other industrial facilities. Monitoring of Premium Standard Farms (PSF) conducted by EPA (under a settlement agreement) in 2004 shows that PSF releases 3 million pounds of ammonia annually from barns and lagoons at its Somerset facility, making it the fifth largest industrial emitter of ammonia in the country.
Threemile Canyon Farms in Boardman, Oregon, reported that its 52,300-dairy-cow operation emits 15,500 pounds of ammonia per day, totaling more than 5,675,000 pounds per year. That is 75,000 pounds more than the nation’s number one manufacturing source of ammonia air pollution CF Industries of Donaldson, Louisiana.
Furthermore, CAFOs produce millions of tons of manure each year. According to EPA, CAFOs generate approximately 500 million tons of waste each year, three times more raw waste than is generated yearly by humans in the U.S.
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